Played quake live, warsow and some quake 3 before and i would like to know what are the biggest difference and similarities compared to those games. Is there a thread or wiki or something to look at the weapon damages and all that kinda stuff?

Welcome! Where are you from (what region of servers do you ping best on)? What kind of game modes do you like? TELL ME EVERYTHING!

Anyway, here's some information.

MOVEMENT

Xonotic's movement is probably most similar to Warsow out of the games you mentioned, except there aren't wall jumps and you have more air control, allowing you to keep momentum through somewhat tight turns. When in the air, you can accelerate simply by going forward, though proper strafe jumping accelerates faster.

Hitting a ramp converts some of your forward momentum to vertical, launching you high into the air.

ITEMS

Health/armor caps at 200/200, and slowly ticks down to 100/100. All health and armor can be picked up to go over 100/100. This is different in XPM balance. XPM isn't like CPM in quake 3, with different weapon balance and physics; it's essentially just tournament settings. In XPM, only shards, 100h, and 100a can be picked up to put you over 100.

Respawn timers are simplified. 100 health, 100 armor, and 50 armor all respawn 30 seconds after being picked up; 50h and 25a are 20s; 25h and shards are 15s; weapons are 10s.

WEAPONS

Weapon switch time is fairly quick in this game. For the weapons with slower refire rates (nex, rocket launcher), it actually makes more sense to switch to another gun and fire after your first shot than to just keep blasting away with the same weapon. Switching and firing nex, rockets, and mortars are the best example of this, and you'll see more experienced players do this all the time. We call this a 'combo'.

Numbers are taken from balanceXonotic.cfg in the game's data pk3. More details on how exactly they work can be found in Halogene's "Basic basics" thread, along with lots of other information you may or may not need.

Secondary (Energy grenades that explode after 3 seconds, or when a player detonates them with a primary blast)
Damage: 40
Push Force: 50
Refire Rate: 0.2 for the first 3 balls, 1.5 before you can fire more balls.
Ammo Usage: 2 Cell